Copper deficiency impairs survival in endotoxin-treated rats

"Free" copper: a new endogenous chemical mediator of inflammation in birds

For acceptance of any chemical agent as an endogenous chemical mediator of inflammation, the agent in question must fulfill some biological requirements which are (a) it should be ubiquitously present in tissues in inactive form, (b) it should be activated during process of inflammation whose increase should be identifiable, (c) it should induce or amplify some events of inflammation, (d) there must be some natural inhibitor of such active form in tissues, (e) it should be able to induce inflammatory reaction after exogenous injection, (f) such reaction should be inhibited by exogenous use of their antagonists, and (g) it should be amplified by use of agonists. Copper in its protein free or protein bound form are reported to act as pathogenic factor in inflammatory processes due to oxidative stress. But their role as endogenous chemical mediator of inflammation does not appear to be investigated thoroughly in light of abovementioned biological criterion of mediator. Present study aims at thorough exploration on role of free copper as endogenous chemical mediator of inflammation in light of above facts. It was done by estimation of total copper, protein-bound copper, and free copper along with estimation of free radical generation, increase in vascular permeability, and cellular infiltration during acute inflammatory reaction induced by carrageenan and concanavalin using chicken skin as test model. It was further evaluated by use of exogenous free copper in experimental model and their subsequent inhibition and amplification by chemical chelators of copper. Present study confirms that free copper fulfilled all the biological requirements for accepting it as an endogenous chemical mediator of inflammation.

Plasma diamine oxidase activities in renal dialysis patients, a human with spontaneous copper deficiency and marginally copper deficient rats

OBJECTIVES

Intestine and kidney are generally the most concentrated sources of the copper metalloenzyme diamine oxidase (DAO). Clinically, plasma DAO activities are used to diagnose disruptions in intestinal integrity. This study determined whether DAO activities were also affected by kidney injury or copper nutritional status.

DESIGN AND METHODS

Plasma DAO activities were measured in renal dialysis patients without diagnosed intestinal disease (n = 75), controls (n = 23), an adult with spontaneous copper deficiency before and after copper repletions, and in rats fed either adequate or marginal copper diets (8 or 2 mg copper/kg diet) for 7 months.

RESULTS

This study found high DAO activities in renal dialysis patients and low activities during spontaneous copper deficiency. Low activities were also seen for marginally copper deficient rats.

CONCLUSIONS

Tissue injury-induced elevation of DAO activities is not limited to intestinal injury, and low DAO values may be useful for assessing copper nutritional status.